JP5531690B2 - Image reading apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to an image reading apparatus and an image forming apparatus.

  In recent years, an image reading apparatus having a double-sided simultaneous reading mechanism capable of simultaneously reading both sides of a document has been proposed for the purpose of improving the productivity of document reading, protecting the document, and improving silence. In such an image forming apparatus, generally, a CCD (Charge Coupled Device) is used for reading the front side of a document, and a CIS (Contact Image Sensor :) is used for reading the back side of the document. A close-contact image sensor is used (see, for example, Patent Documents 1 and 2).

  Some CISs have an image processing function inside the CIS module. In such a CIS, correction between lines within the CIS module is required before image processing. However, in order to reduce the cost by reducing the memory for correction between lines, a fixed resolution (scanning in the sub-scan direction) is required. It may be premised on reading at (speed).

  When the resolution is fixed in this way, the CIS cannot change the resolution mechanically by changing the resolution even if the magnification is designated. For this reason, the CIS always reads a document with a fixed resolution (same size) regardless of the scaling factor even when scaling is designated. Then, the subsequent image processing unit and control unit scales the image data read by the CIS to a designated magnification by an electrical scaling process.

  For example, it is assumed that the fixed resolution is 600 dpi and the magnification is changed to 50%. In this case, if the resolution is variable, it is possible to read the original at 300 dpi, read the original at twice the reading speed in the sub-scanning direction as compared with reading the original at 600 dpi, and perform mechanical scaling. It becomes. However, in CIS with a fixed resolution, it is not possible to perform mechanical scaling by reading an original at 300 dpi. After scanning an original at 600 dpi, the magnification is changed to 300 dpi by electrical scaling. There must be.

  As described above, even if the resolution is fixed, the magnification can be changed by an electric scaling process. However, the reading speed of the document is lower than that in the case of mechanical scaling. There is a problem that productivity is lowered.

  The present invention has been made in view of the above circumstances, and is an image reading apparatus and an image forming apparatus capable of reducing costs and preventing a decrease in productivity even when electrical scaling is performed. An object is to provide an apparatus.

In order to solve the above-described problems and achieve the object, an image reading apparatus according to an aspect of the present invention is configured to display one side of a document with a first resolution corresponding to a variable magnification and a predetermined first reading cycle. First image reading means that scans and reads first image data and a light source are turned on, the other surface of the original is irradiated, reflected light from the original is received and accumulated, and converted into second image data to a second image reading unit, wherein the second image reading means scans the other surface of the document in the second reading period corresponding to a fixed second resolution and the magnification was, the document The light accumulation time which is the time for accumulating the reflected light from the light is controlled to be constant.

  An image forming apparatus according to another aspect of the present invention includes the image reading apparatus.

  According to the present invention, even when electrical zooming is performed, the cost can be reduced and the productivity can be prevented from being lowered.

FIG. 1 is a configuration diagram illustrating a schematic configuration example of the scanner device of the first embodiment. FIG. 2 is a block diagram illustrating a hardware configuration example of the multifunction peripheral according to the first embodiment. FIG. 3 is a flowchart illustrating an example of double-sided reading processing of the multifunction machine according to the first embodiment. FIG. 4 is a timing chart illustrating an example of signals exchanged between the input image processing unit and the CIS according to the first embodiment when performing the equal magnification reading. FIG. 5 is a timing chart illustrating an example of signals exchanged between the input image processing unit and the CIS according to the first embodiment when performing variable magnification reading with a variable magnification of 1/2. FIG. 6 is a flowchart illustrating an example of double-sided reading processing performed by the multifunction machine according to the first modification. FIG. 7 is a flowchart illustrating an example of double-sided reading processing performed by the multifunction machine according to the second modification. FIG. 8 is a flowchart illustrating an example of a reading process performed by the multifunction machine according to the third modification. FIG. 9 is a configuration diagram illustrating a schematic configuration example of the scanner device of the second embodiment. FIG. 10 is a block diagram illustrating a hardware configuration example of the multifunction machine according to the second embodiment. FIG. 11 is a flowchart illustrating an example of double-sided reading processing of the multifunction machine according to the second embodiment. FIG. 12 is a timing chart illustrating an example of signals exchanged between the input image processing unit and the CIS according to the second embodiment when performing equal magnification reading. FIG. 13 is a timing chart illustrating an example of signals exchanged between the input image processing unit and the CIS according to the second embodiment when performing variable magnification reading at a variable magnification of 1/2.

  Hereinafter, embodiments of an image reading apparatus and an image forming apparatus according to the present invention will be described in detail with reference to the accompanying drawings. In each of the following embodiments, as an image forming apparatus, a multifunction peripheral (MFP) having at least one of a print function, a copy function, and a facsimile function in addition to a scanner function will be described as an example. However, the present invention is not limited to this. For example, a copying machine or a scanner device may be used.

(First embodiment)
First, the configuration of the MFP according to the first embodiment will be described.

  FIG. 1 is a configuration diagram illustrating an example of a schematic configuration of a scanner device 100 (an example of an image reading device) included in the multifunction machine 10 according to the first embodiment. As shown in FIG. 1, the scanner device 100 includes an image reading unit 110 (an example of a first image reading unit) that reads the surface of a document at a lower portion thereof, and an ADF (Auto Document Feeder) that conveys the document at an upper portion thereof. : Document transport device) 140. The ADF 140 includes a CIS (contact close-magnification image sensor) 150 (an example of a second image reading unit) that reads the back side of the document.

  The image reading unit 110 irradiates the slit glass 112 through which the original conveyed by the ADF 140 passes, the contact glass 114 on which the original to be read is placed, the reference white plate 116 for generating shading correction data, and the original to be read. The first carriage 122 on which the lamp 118 and the first mirror 120 are mounted, the second carriage 128 on which the second mirror 124 and the third mirror 126 are mounted, and the lens unit 132 that reduces the image on the CCD image sensor 130. And a signal processing board 134 that mounts the CCD image sensor 130, performs predetermined processing on the image signal output from the CCD image sensor 130, and outputs the processed image signal to the outside. The lamp 118 may be a light source, and for example, an LED (Light Emitting Diode) may be used. The image reading unit 110 also includes a drive motor that drives the first carriage 122 and the second carriage 128, a home position sensor that detects a home position, a document detection sensor that detects a document (all not shown), and the like.

  The image reading unit 110 can read the surface of the document by the placement reading method or the sheet-through reading method.

  The placement reading method is a reading method in which the lamp 118 is turned on, the first carriage 122 and the second carriage 128 are moved and scanned in the sub-scanning direction by a driving motor, and the surface of the document placed on the contact glass 114 is read. It is. In the case of the placement reading method, the image reading unit 110 acquires the data of the reference white plate 116 prior to reading the document, and generates shading correction data. Then, the image reading unit 110 executes shading correction processing in parallel with scanning (reading operation) of the document reading area.

  In the sheet-through reading method, the surface of the original is read when the original conveyed by the ADF 140 passes through the upper part of the slit glass 112 while the lamp 118 is turned on and the first carriage 122 and the second carriage 128 are stopped. This is a reading method. In the case of the sheet-through reading method, the image reading unit 110 generates shading correction data by moving the first carriage 122 and the second carriage 128 below the reference white plate 116 by a drive motor prior to reading a document. Then, the image reading unit 110 returns the first carriage 122 and the second carriage 128 to the sheet-through reading position by the driving motor, and then is parallel to the scanning (reading operation) of the document reading area of the document conveyed by the ADF 140. To execute shading correction processing.

  In the case of the sheet-through reading method, the back side of the document can be read using the CIS 150. That is, in the sheet-through reading method, it is possible to read only the surface of the document, or it is possible to simultaneously read both sides of the document.

  The ADF 140 includes a document tray 142 on which a document is placed, a reference white roller 144 provided at a position facing the CIS 150, a discharge tray 146 for discharging the document, and a document transport mechanism 148 (an example of a transport unit). Prepare. The ADF 140 also includes a drive motor (not shown) that drives the document conveyance mechanism 148. When sheet-through reading is performed by the image reading unit 110, the document transport mechanism 148 passes the document placed on the document tray 142 through the upper portion of the slit glass 112 and the CIS 150 and the reference white roller 144. The paper is conveyed to the paper discharge tray 146.

  The CIS 150 includes an LED 152 as a light source, and also includes a lens array, a sensor element (both not shown), and the like. When simultaneously reading both sides of a document by the sheet-through reading method, the CIS 150 turns on the LED 152, irradiates the back surface of the document that is transported by the ADF 140 and passes through the lower part of the CIS 150, and reflects light from the document with a lens array And condensed into image data. As a result, the CIS 150 reads the back side of the document conveyed by the ADF 140. Note that the CIS 150 acquires data of the reference white roller 144 prior to reading the document, and generates shading correction data. The CIS 150 executes a shading correction process in parallel with the scanning (reading operation) of the document reading area.

  In the first embodiment, an example in which the image reading unit 110 reads the front surface of the document and the CIS 150 reads the back surface of the document will be described. However, the image reading unit 110 reads the back surface of the document and the CIS 150 reads the front surface of the document. You can do it. Further, the image reading unit 110 does not have to have all the above-described configurations as essential configurations, and may be configured such that some of them are omitted.

  FIG. 2 is a block diagram illustrating an example of a hardware configuration of the multifunction machine 10 according to the first embodiment. As illustrated in FIG. 2, the multifunction machine 10 includes an image reading unit 110, a CIS 150, an image processing unit 210, and a controller 240.

  The image processing unit 210 includes a data conversion unit 212, a data conversion unit 214, a CPU (Central Processing Unit) 216, a CPU memory 218, a memory control unit 220, and an input image processing unit 222 (an example of a scaling unit). And a bus 224 for connecting these units. The image processing unit 210 also includes a memory 226 connected to the memory control unit 220, an output image processing unit 228 connected to the input image processing unit 222, and an LD (connected to the output image processing unit 228. A laser diode) driver 230. In the configuration illustrated in FIG. 2, for example, the image reading unit 110, the CIS 150, and the image processing unit 210 (except for the output image processing unit 228 and the LD driver 230) correspond to the scanner device 100.

  The image reading unit 110 reads the image data on the surface of the document, and transfers the read image data to the input image processing unit 222 via the data conversion unit 212 and the memory control unit 220. Specifically, the signal processing board 134 performs predetermined processing such as A / D conversion processing, signal amplification processing, and shading processing on the image data (image signal) output from the CCD image sensor 130, and thereby the input image. Transfer to the processing unit 222.

  Here, it is assumed that the image reading unit 110 has variable resolution. For this reason, the CPU 216 controls the drive motor to cause the document transport mechanism 148 to transport the document at a transport speed corresponding to the variable magnification, and the image reading unit 110 changes the resolution according to the variable magnification to change the surface of the document. By scanning the image data and reading the image data, the magnification can be changed mechanically. For example, when 50% zooming is designated, the CPU 216 causes the document transport mechanism 148 to transport the document at a transport speed that is twice that in the case of the same magnification scanning, and the image reading unit 110 performs resolution scanning at the same magnification. When the image data is read by scanning the surface of the original in half of the case, the magnification can be mechanically changed by 50%.

  The CIS 150 reads image data on the back side of the document, and transfers the read image data to the input image processing unit 222 via the data conversion unit 214 and the memory control unit 220. Specifically, the CIS 150 performs predetermined processing such as A / D conversion processing, signal amplification processing, and shading processing on the read image data (image signal) and transfers the processed image data to the input image processing unit 222.

  Here, the CIS 150 performs line-to-line correction before performing the above-described image processing. In order to reduce the cost by reducing the memory for line-to-line correction, the CIS 150 has a fixed resolution (scanning in the sub-scanning direction). It is assumed that the data is read at a speed. Therefore, when reading both sides of a document by the sheet-through reading method, the CIS 150 always reads image data on the back side of the document with a fixed resolution (same size). Even with this reading method, the magnification can be electrically reduced (reduced), but the reading speed of the document is lowered and the productivity is lowered as compared with the case where mechanical magnification is performed.

  Therefore, in the first embodiment, the CPU 216 controls the drive motor to transport the document to the document transport mechanism 148 at a transport speed corresponding to the variable magnification, and the CIS 150 changes the reading line cycle according to the variable magnification. The back side of the document is scanned to read the image data, and the input image processing unit 222 electrically scales the read image data. For example, when 50% scaling is designated, the CPU 216 causes the document transport mechanism 148 to transport the document at twice the transport speed in the case of the same magnification scanning, and the CIS 150 performs the scanning of the scanning line cycle at the same magnification. The input image processing unit 222 electrically scales the read image data to 50%. As a result, even when the resolution is fixed and electrical scaling is performed, it is possible to prevent a decrease in the reading speed of the document and a decrease in productivity, and the same productivity as when mechanical scaling is performed. Can keep.

  However, simply shortening the reading line period in accordance with the magnification (reduction ratio) also shortens the light accumulation time of the light emitted from the LED 152, leading to a change in reading characteristics such as a decrease in S / N, for example. Deterioration (change) in image quality occurs.

  Therefore, in the first embodiment, the CIS 150 controls the optical accumulation time to be equal to or less than a lower limit value (constant) of the reading line cycle. Specifically, the CIS 150 controls the lighting of the LED 152 to control the light accumulation time to be equal to or less than the lower limit value of the reading line cycle. Thereby, even if the reading line cycle is changed according to the magnification, the light accumulation time can be kept constant, and a change in reading characteristics and a deterioration in image quality can be prevented.

  The data conversion unit 212 converts the format of the image data input from the image reading unit 110 into a format compatible with the input image processing unit 222. The data conversion unit 214 converts the format of the image data input from the CIS 150 into a format compatible with the input image processing unit 222.

  The memory control unit 220 temporarily writes the image data input from the data conversion unit 212 and the data conversion unit 214 to the memory 226, reads the written image data from the memory 226, and transfers the image data to the input image processing unit 222.

  The input image processing unit 222 performs image processing due to input characteristics such as γ correction and MTF (Modulation Transfer Function) correction, scaling processing, and the like on the image data transferred from the memory control unit 220, and the controller 240. Forward to. Further, the input image processing unit 222 outputs the image data transferred from the controller 240 to the output image processing unit 228.

  The output image processing unit 228 performs image processing according to output characteristics such as filter processing and color space conversion processing on the image data input from the input image processing unit 222 and outputs the processed image data to the LD driver 230.

  The LD driver 230 drives the LD according to the image data input from the output image processing unit 228, and irradiates a photoconductor of an image forming unit (not shown) with laser light. An electrostatic latent image is formed on the photoreceptor, and a print image is output through transfer and fixing.

  The CPU 216 uses the CPU memory 218 as a work area to control each unit of the image processing unit 210, the image reading unit 110, the CIS 150, and the ADF 140. The CPU 216 communicates with the CPU 242 of the controller 240 to transmit / receive various data. Note that the CPU 216 may perform scaling processing performed by the input image processing unit 222 in hardware.

  The controller 240 includes a CPU 242, an image controller 244 connected to the CPU 242, an I / O controller 246 connected to the CPU 242, and an input unit 248 connected to the I / O controller 246.

  The image controller 244 stores the image data transferred from the input image processing unit 222 in an HDD (Hard Disk Drive) (not shown) or the like. Further, the image controller 244 reads out image data stored in the HDD and transfers it to the image processing unit 210.

  An input unit 248 (an example of a mode input unit) performs various inputs such as an input for instructing reading start of a document and an input of a reading mode.

  The CPU 242 controls each part of the controller 240. The CPU 242 communicates with the CPU 216 of the image processing unit 210 and transmits / receives various data such as data input from the input unit 248 via the I / O controller 246.

  Next, the operation of the multifunction machine of the first embodiment will be described.

  FIG. 3 is a flowchart illustrating an example of a flow of a double-sided reading process performed by the multifunction machine 10 according to the first embodiment. In the example illustrated in FIG. 3, the input unit 248 is set in a state where a document is placed on the document tray 142 of the ADF 140 and the double-sided reading mode is set by the input image processing unit 222 based on an input from the input unit 248. It is assumed that a reading start input has been made. In FIG. 3, when the range of mechanical magnification is 50% to 100% (300 dpi to 600 dpi) and the scanner device 100 performs the same magnification reading, the reading linear velocity is 300 mm / sec, and the surface reading line cycle However, the present invention is not limited to this example. However, this is not limited to 141 μsec, the surface reading resolution is 600 dpi, the back surface scanning line period is 141 μsec, and the back surface scanning resolution is 600 dpi.

  First, when receiving a reading start input from the input unit 248 via the CPU 242, the CPU 216 sets the lighting duty of the LED 152 to be equal to or lower than the lower limit value of the back surface scanning line cycle. Although details will be described later, in the example shown in FIG. 3, the lower limit value of the back surface scanning line cycle is 70.5 (141 × 1/2) μsec, so the CPU 216 sets the lighting duty of the LED 152 to 70 μsec. (Step S100).

  Subsequently, the CPU 216 sets the surface reading line cycle (an example of the first reading cycle) to 141 μsec (step S102).

  Subsequently, when zooming input for inputting a zooming ratio from the input unit 248 is performed before the reading start input (Yes in step S104), the CPU 216 responds to the zooming ratio received from the input unit 248 via the CPU 242. To set the reading linear speed (an example of the conveyance speed). Specifically, the CPU 216 sets a speed obtained by dividing 300 mm / sec, which is the reading linear speed when performing equal magnification reading, by the variable magnification as the reading linear speed (step S106). For example, when the variable magnification is 1/2 (50%), the CPU 216 sets the reading linear velocity to 600 (300 / (1/2)) mm / sec. Here, in the example shown in FIG. 3, since the range of zooming is 50% to 100%, the reading linear velocity is set in the range of 300 mm / sec to 600 mm / sec.

  Subsequently, the CPU 216 sets a back surface scanning line cycle (an example of a second scanning cycle) according to the scaling factor received from the input unit 248 via the CPU 242. Specifically, the CPU 216 sets a cycle obtained by multiplying 141 μsec, which is the back side scanning line cycle in the case of performing equal magnification scanning, by the variable magnification as the back side scanning line cycle (step S108). For example, when the variable magnification is 1/2 (50%), the CPU 216 sets the back surface scanning line cycle to 70.5 (141 × 1/2) μsec. Here, in the example shown in FIG. 3, since the range of magnification is 50% to 100%, the back surface scanning line cycle is set in the range of 70.5 μsec to 141 μsec, and the lower limit value of the back surface scanning line cycle is 70.5 μsec.

  Subsequently, the CPU 216 sets the surface reading resolution (an example of the first resolution) in accordance with the scaling factor received from the input unit 248 via the CPU 242. Specifically, the CPU 216 sets a resolution obtained by multiplying 600 dpi, which is a surface reading resolution in the case of performing the same magnification reading, by a variable magnification as the surface reading resolution (step S110). For example, when the scaling factor is 1/2 (50%), the CPU 216 sets the surface reading resolution to 300 (600 × 1/2) dpi. Here, in the example shown in FIG. 3, since the range of zooming is 50% to 100%, the surface reading resolution is set in the range of 300 dpi to 600 dpi. Note that the back side scanning resolution (an example of the second resolution) is fixed at 600 dpi.

  On the other hand, if the scaling input for inputting the scaling ratio is not performed from the input unit 248 before the reading start input (No in step S104), the CPU 216 reads 300 mm / sec, which is the scanning linear speed when performing the equal magnification scanning. Is set to the reading linear velocity (step S112).

  Subsequently, the CPU 216 sets 141 μsec, which is the back surface reading line cycle when performing the same magnification reading, as the back surface reading line cycle (step S114).

  Subsequently, the CPU 216 sets the surface reading resolution of 600 dpi, which is the surface reading resolution when performing the normal magnification reading (step S116). Note that the back surface reading resolution is fixed at 600 dpi.

  When the setting of various parameters is completed and the CPU 216 starts controlling the drive motor, the document transport mechanism 148 starts transporting the document at the reading linear speed set by the CPU 216 (step S118).

  Subsequently, the image reading unit 110 reads the image data of the surface of the document conveyed by the document conveying mechanism 148 according to the surface reading line period and the surface reading resolution set by the CPU 216, and the CIS 150 is set by the CPU 216. The image data on the back side of the document transported by the document transport mechanism 148 is read in accordance with the lighting duty and the back surface reading line cycle (step S120).

  FIG. 4 is a timing chart illustrating an example of signals exchanged between the input image processing unit 222 and the CIS 150 when performing the same magnification reading.

  In the example shown in FIG. 4, a line synchronization signal is generated by the CIS 150 every 141 μsec that is the back surface reading line cycle and is input to the input image processing unit 222. In addition, generation of a lamp lighting signal indicating lighting of the LED 152 in synchronization with the line synchronization signal is started in the CIS 150 and is input to the input image processing unit 222 for 70 μsec set by the lighting duty. Further, an image signal is input from the CIS 150 to the input image processing unit 222 within the back surface scanning line cycle.

  That is, in the example shown in FIG. 4, the CIS 150 starts reading image data for one line on the back side of the document every 141 μsec and lights the LED 152 for a period of 70 μsec. Then, the CIS 150 reads the image data for one line on the back side of the document within a period of 141 μsec and outputs it to the input image processing unit 222.

  FIG. 5 is a timing chart illustrating an example of signals exchanged between the input image processing unit 222 and the CIS 150 when performing variable magnification reading at a variable magnification of 1/2.

  In the example shown in FIG. 5, a line synchronization signal is generated by the CIS 150 every 70.5 μsec that is the back surface reading line cycle and is input to the input image processing unit 222. In addition, generation of a lamp lighting signal indicating lighting of the LED 152 in synchronization with the line synchronization signal is started in the CIS 150 and is input to the input image processing unit 222 for 70 μsec set by the lighting duty. Further, an image signal is input from the CIS 150 to the input image processing unit 222 within the back surface scanning line cycle. Note that the pixel clock frequency is a frequency at which effective image data can be transferred even when the back side scanning line cycle is changed according to the magnification, and the back side scanning line cycle is changed according to the magnification. It is possible.

  That is, in the example shown in FIG. 5, the CIS 150 starts reading image data for one line on the back side of the document every 70.5 μsec, and lights the LED 152 for a period of 70 μsec. Then, the CIS 150 reads the image data for one line on the back side of the document within a period of 70.5 μsec and outputs it to the input image processing unit 222.

  In the case of the example shown in FIG. 5, the image data for one line on the surface of the document read by the image reading unit 110 is mechanically scaled to 50% (300 dpi) in the sub-scanning direction. However, the image data for one line on the back side of the document read by the CIS 150 is not scaled. For this reason, the input image processing unit 222 electrically scales to 50% (300 dpi) in the sub-scanning direction.

  Then, the image reading unit 110 ends the reading when reading the image data for all the lines on the front side of the document, and the CIS 150 ends the reading when reading the image data for all the lines on the back side of the document (step S122). .

  Subsequently, when the CPU 216 finishes controlling the drive motor, the document transport mechanism 148 ends the transport of the document (step S124).

  As described above, in the first embodiment, even when the resolution is fixed, the reading line speed is increased in accordance with the reduction rate, and the reading line cycle is shortened in accordance with the reduction rate. Therefore, it is possible to prevent a reduction in document reading speed and a decrease in productivity, and maintain the same productivity as in the case of mechanical scaling.

  In the first embodiment, since the lighting duty of the LED 152 is controlled to be equal to or lower than the lower limit value of the reading line cycle, the light accumulation time can be kept constant even if the reading line cycle is changed according to the variable magnification. It is possible to prevent changes in reading characteristics and image quality deterioration. It is assumed that the lighting duty of the LED 152 is designed for an illumination system having an illuminance necessary to satisfy the reading performance (S / N) of the scanner 100.

(Modification 1)
In the first embodiment, the example in which the front surface of the document is mechanically scaled and the back surface of the document is electrically scaled has been described. In the first modification, an example in which scaling is performed in the above-described manner or both sides of the document are electrically scaled is selected depending on whether image data productivity is given priority or reusability is given priority. Will be described. In the following, differences from the first embodiment will be mainly described, and description of components having functions similar to those of the first embodiment will be omitted.

  FIG. 6 is a flowchart illustrating an example of a flow of a double-sided reading process performed by the multifunction machine 10 according to the first modification.

  First, the processing from step S200 to S204 is the same as the processing from step S100 to S104 in the flowchart shown in FIG.

  In step S205, when the input of the productivity mode giving priority to the productivity of the image data is performed from the input unit 248 before the reading start input (Yes in step S205), the process proceeds to step S206, and the reusability of the image data is performed. If the reusability mode that gives priority to the input is input (No in step S205), the process proceeds to step S212.

  The processes in steps S206 to S210 and steps S218 to S224 when the productivity mode is input are the same as the processes in steps S106 to S110 and steps S118 to S124 in the flowchart shown in FIG. Therefore, the description is omitted.

  Further, when the reusability mode is input, the processes from step S212 to S218 and steps S222 to S224 are the same as steps S112 to S118 and steps S122 to S124 in the flowchart shown in FIG. Since it is the same as the processing, the description is omitted.

  In step S220 when the reusability mode is input, the input image processing unit 222 reads the image data on the front side of the document read by the image reading unit 110 and the image on the back side of the document read by the CIS 150. Data is transferred to the image controller 244 and stored in the HDD or the like. The input image processing unit 222 receives the transfer of the front and back image data stored in the HDD or the like from the image controller 244, and performs electrical scaling.

  That is, in the reusability mode, even when scaling is performed, both the front and back sides of the document are scanned at the same magnification, and after the image data read at the same magnification is stored, the input image processing unit 222 is stored. Electrical scaling to the scaling factor specified by is performed.

  Thus, in the reusability mode, even when scaling is performed, the image data read at the same magnification is stored, so that the stored image data is different from the scaling ratio specified at the time of reading. It is possible to change the magnification at the magnification and output it as a copy image or to send it by FAX, thereby improving the reusability of the image data.

(Modification 2)
In the first embodiment, the example in which the front surface of the document is mechanically scaled and the back surface of the document is electrically scaled has been described. In the second modification, scaling is performed in the above-described manner or both sides of the document are electrically scaled depending on whether the scanner application mode performs scanning using the scanner application or the copy application mode performs scanning using the copy application. An example of selecting these will be described. In the following, differences from the first embodiment will be mainly described, and description of components having functions similar to those of the first embodiment will be omitted.

  FIG. 7 is a flowchart illustrating an example of a flow of a double-sided reading process performed by the multifunction machine 10 according to the second modification.

  First, the processing from step S300 to S304 is the same as the processing from step S100 to S104 in the flowchart shown in FIG.

  In step S305, if the scanner application mode is input from the input unit 248 before the reading start input (Yes in step S305), the process proceeds to step S306, and if the copy application mode is input (step S305). No), the process proceeds to step S312.

  The processes in steps S306 to S310 and steps S318 to S324 when the scanner application mode is input are the same as the processes in steps S106 to S110 and steps S118 to S124 in the flowchart shown in FIG. Therefore, the description is omitted.

  Further, the processes from step S312 to S318 and steps S322 to S324 when the copy application mode is input are the processes from step S112 to S118 and steps S122 to S124 in the flowchart shown in FIG. Since it is the same as that, description is abbreviate | omitted.

  In step S320 when the copy application mode is input, the input image processing unit 222 reads the image data of the front side of the document read by the image reading unit 110 and the image data of the back side of the document read by the CIS 150. Is transferred to the image controller 244 and stored in the HDD or the like. Then, the input image processing unit 222 receives the transfer of the front and back image data stored in the HDD or the like from the image controller 244, performs electrical scaling, and outputs it to the output image processing unit 228 for copying images. As output.

  That is, in the copy application mode, even when scaling is performed, both the front and back of the document are scanned at the same magnification, and after the image data read at the same magnification is stored, the input image processing unit 222 Electrical scaling to the designated scaling ratio is performed and a copy image is output.

  In this way, the productivity of image data can be prioritized in the scanner application mode, and the reusability of image data can be prioritized in the copy application mode. In the second modification, the example in which the image data productivity is given priority in the scanner application mode and the reusability of the image data is given priority in the copy application mode has been described, but the relationship between each application mode and what has priority. Is not limited to this. For example, priority may be given to image data reusability in the scanner application mode, and image data productivity may be given priority in the copy application mode. You may make it input from the input part 248 whether to do.

(Modification 3)
In the first embodiment, the example in which the front surface of the document is mechanically scaled and the back surface of the document is electrically scaled has been described. In Modification 3, in the case of single-sided scanning, the surface of the document is mechanically scaled. In the case of double-sided scanning, both sides of the document are electrically scaled, or the surface of the document is mechanically and mechanically changed. An example in which the magnification is electrically changed and the back side of the document is electrically changed will be described. In the following, differences from the first embodiment will be mainly described, and description of components having functions similar to those of the first embodiment will be omitted.

  FIG. 8 is a flowchart illustrating an example of a flow of a reading process performed by the multifunction machine 10 according to the third modification. In the example illustrated in FIG. 8, a reading start input is performed from the input unit 248 in a state where a document is placed on the document tray 142 of the ADF 140 and the scaling unit is input from the input unit 248. It shall be In FIG. 8, the range of mechanical scaling is 400 dpi to 600 dpi, and the scaling of the surface of the original to 300 dpi to 400 dpi is performed by using both mechanical scaling and electrical scaling. And

  First, when receiving a reading start input from the input unit 248 via the CPU 242, the CPU 216 sets the lighting duty of the LED 152 to be equal to or lower than the lower limit value of the back surface scanning line cycle. Although details will be described later, in the example shown in FIG. 8, the lower limit value of the back surface scanning line cycle is 94 (141 × 2/3) μsec. Therefore, the CPU 216 sets the lighting duty of the LED 152 to 93 μsec. (Step S400).

  Subsequently, the CPU 216 sets the surface reading line cycle to 141 μsec (step S402).

  Subsequently, when the single-sided reading mode is input from the input unit 248 before the reading start input (No in step S404), the CPU 216 reads the reading line according to the variable magnification received from the input unit 248 via the CPU 242. Set the speed. Specifically, the CPU 216 sets a speed obtained by dividing 300 mm / sec, which is a reading linear speed when performing equal magnification reading, by a variable magnification as the reading linear speed (step S406).

  Subsequently, the CPU 216 sets the surface reading resolution according to the scaling factor received from the input unit 248 via the CPU 242. Specifically, the CPU 216 sets a resolution obtained by multiplying 600 dpi, which is the surface reading resolution in the case of performing the same magnification reading, by the variable magnification as the surface reading resolution (step S408).

  On the other hand, when the double-sided reading mode is input from the input unit 248 before the reading start input (Yes in step S404), the zooming range indicated by the zooming factor accepted by the CPU 216 is within a range of 300 dpi to 400 dpi (step). In S410, the CPU 216 sets the reading linear velocity to 450 (300 / (2/3)) mm / sec (step S412).

  Subsequently, the CPU 216 sets the back surface scanning line cycle to 94 (141 × 2/3) μsec (step S414). Here, in the example shown in FIG. 8, since the range of mechanical magnification is 400 dpi to 600 dpi, the back surface scanning line cycle is in the range of 94 μsec to 141 μsec, and the lower limit value of the back surface scanning line cycle is 94 μsec. .

  Subsequently, the CPU 216 sets the surface reading resolution to 400 (600 × 2/3) dpi (step S416). Note that the back surface reading resolution is fixed at 600 dpi.

  Further, when the input of the double-sided reading mode is performed from the input unit 248 before the reading start input (Yes in step S404), and the zooming range indicated by the zooming factor accepted by the CPU 216 is outside the range of 300 dpi to 400 dpi (step) In step S410, the CPU 216 sets 300 mm / sec, which is the reading linear velocity when performing the same magnification reading, as the reading linear velocity (step S418).

  Subsequently, the CPU 216 sets 141 μsec, which is the back surface scanning line cycle when performing the normal scanning, as the back surface scanning line cycle (step S420).

  Subsequently, the CPU 216 sets 600 dpi, which is the surface reading resolution when performing the normal magnification reading, as the surface reading resolution (step S422). Note that the back surface reading resolution is fixed at 600 dpi.

  When the setting of various parameters is completed and the CPU 216 starts controlling the drive motor, the document transport mechanism 148 starts transporting the document at the reading linear speed set by the CPU 216 (step S424).

  Subsequently, in step S426 when the single-sided reading mode is input (No in step S404), the image reading unit 110 causes the document conveying mechanism according to the surface reading line period and the surface reading resolution set by the CPU 216. The image data on the surface of the original conveyed by 148 is read. In this case, the image data on the surface of the document read by the image reading unit 110 is mechanically scaled to a magnification specified in the sub-scanning direction.

  In addition, in step S426 when the duplex scanning mode is input and the zooming range is within the range of 300 dpi to 400 dpi (Yes in step S410), the image reading unit 110 causes the front side scanning line cycle set by the CPU 216 to be set. The image data on the surface of the document conveyed by the document conveyance mechanism 148 is read in accordance with the surface reading resolution and the like. Further, the CIS 150 reads the image data on the back side of the document conveyed by the document conveyance mechanism 148 in accordance with the lighting duty and the back surface reading line period set by the CPU 216.

  In this case, the image data on the front side of the document read by the image reading unit 110 is mechanically scaled to 400 dpi in the sub-scanning direction, and the image data on the back side of the document read by the CIS 150 is scaled. Is not done. For this reason, the input image processing unit 222 further changes the electric data in the sub-scanning direction so that the specified magnification is obtained when the image data scaled to 400 dpi is transferred from the image reading unit 110. Do it twice. Similarly, when the image data on the back side of the document is transferred from the CIS 150, the input image processing unit 222 performs electrical scaling to a magnification specified in the sub-scanning direction.

  In addition, in step S426 when the double-sided reading mode is input and the zooming range is out of the range of 300 dpi to 400 dpi (No in step S410), the image reading unit 110 causes the surface reading line cycle set by the CPU 216. The image data on the surface of the document conveyed by the document conveyance mechanism 148 is read in accordance with the surface reading resolution and the like. Further, the CIS 150 reads the image data on the back side of the document conveyed by the document conveyance mechanism 148 in accordance with the lighting duty and the back surface reading line period set by the CPU 216.

  In this case, the image data on the front side of the document read by the image reading unit 110 and the image data on the back side of the document read by the CIS 150 are not scaled. For this reason, when the image data on the surface of the document is transferred from the image reading unit 110, the input image processing unit 222 performs electrical scaling to the magnification specified in the sub-scanning direction, and similarly, the input image When image data on the back side of the document is transferred from the CIS 150, the processing unit 222 performs electrical scaling to a magnification specified in the sub-scanning direction.

  Then, the image reading unit 110 ends the reading when reading the image data for all the lines on the front side of the document, and the CIS 150 ends the reading when reading the image data for all the lines on the back side of the document (step S428). .

  Subsequently, when the CPU 216 finishes controlling the drive motor, the document transport mechanism 148 ends the transport of the document (step S430).

  In this way, only mechanical scaling is performed in the single-sided reading mode, so that productivity can be maximized.

  Further, in the double-sided reading mode, when the reduction ratio is large (in the case of 300 dpi to 400 dpi), the magnification is changed by combining mechanical magnification and electrical magnification. For example, when scaling to 350 dpi, the image data on the surface of the document is first mechanically scaled from 600 dpi to 400 dpi, and then electrically scaled to 350 dpi. Image data on the back side of the document is electrically scaled from 600 dpi to 350 dpi.

  As a result, the lower limit of the back surface scanning line cycle can be increased and the lighting duty of the LED 152 can be increased as compared with the case where the scaling of the image data on the front side of the document is handled only by mechanical scaling. . As a result, the illuminance of the LED 152 can also be reduced, and the occurrence of side effects such as an increase in cost and an increase in heat generation can be suppressed. In other words, by using mechanical zooming and electrical zooming together, it is possible to suppress the occurrence of side effects as described above while maintaining productivity.

(Modification 4)
The first to third modifications described above can be combined as appropriate. The first modification and the third modification may be combined to select whether to give priority to productivity or reusability when performing single-sided reading or double-sided reading.

(Second Embodiment)
In the first embodiment, the example in which the light accumulation time is controlled by controlling the lighting of the LED has been described. In the second embodiment, an example in which the light accumulation time is controlled using the electronic shutter function of the CIS will be described. . In the following, differences from the first embodiment will be mainly described, and components having the same functions as those in the first embodiment will be given the same names and symbols as those in the first embodiment, and the description thereof will be made. Omitted.

  FIG. 9 is a configuration diagram illustrating an example of a schematic configuration of a scanner device 1100 (an example of an image reading device) included in the multifunction peripheral 1010 according to the second embodiment. FIG. 10 is a block diagram illustrating an example of a hardware configuration of the MFP 1010 according to the second embodiment. In the MFP 1010 of the second embodiment, the CIS 1150 and the input image processing unit 1222 of the image processing unit 1210 are different from the MFP 10 of the first embodiment.

  Unlike the CIS 150 of the first embodiment, the CIS 1150 includes a xenon lamp 1152 as a light source. The xenon lamp 1152 is difficult to control on / off in one line cycle from the viewpoint of responsiveness. Therefore, in the CIS 1150 of the second embodiment, the lighting time of the xenon lamp 1152 is not controlled but the electronic shutter function is used to control the light accumulation time to be lower than the lower limit value of the reading line cycle. However, even when an LED is used as the light source, the same control using the electronic shutter function can be performed.

  FIG. 11 is a flowchart illustrating an example of a flow of a double-sided reading process performed by the multifunction machine 1010 according to the second embodiment. The preconditions are the same as those in the flowchart shown in FIG.

  First, when receiving a reading start input from the input unit 248 via the CPU 242, the CPU 216 sets the electronic shutter setting of the CIS 1150 to be equal to or lower than the lower limit value of the back surface scanning line cycle. In the example shown in FIG. 11, since the lower limit value of the back surface scanning line cycle is 70.5 (141 × 1/2) μsec, the CPU 216 sets the electronic shutter setting to 70 μsec (step S1100).

  Subsequently, the processing from step S1102 to S1118 is the same as the processing from step S102 to S118 in the flowchart shown in FIG.

  In step S 1120, the image reading unit 110 reads image data on the surface of the document conveyed by the document conveying mechanism 148 according to the surface reading line period and surface reading resolution set by the CPU 216, and the CIS 1150 is set by the CPU 216. The image data on the back side of the document transported by the document transport mechanism 148 is read in accordance with the electronic shutter setting and the back surface scanning line cycle.

  FIG. 12 is a timing chart illustrating an example of signals exchanged between the input image processing unit 1222 and the CIS 1150 when performing the same magnification reading.

  In the example illustrated in FIG. 12, a line synchronization signal is generated by the CIS 1150 every 141 μsec that is the back surface reading line cycle and is input to the input image processing unit 1222. Also, generation of an electronic shutter control signal indicating release of the electronic shutter is started in CIS 1150 in synchronization with the line synchronization signal, and is input to the input image processing unit 1222 for 70 μsec set by the electronic shutter setting. An image signal is input from the CIS 1150 to the input image processing unit 1222 within the back surface scanning line period. The lamp lighting signal is input during the image reading period.

  That is, in the example shown in FIG. 12, the CIS 1150 starts reading image data for one line on the back side of the document every 141 μsec, and releases the electronic shutter for a period of 70 μsec and accumulates light. Then, the CIS 1150 reads the image data for one line on the back side of the document within a period of 141 μsec and outputs it to the input image processing unit 1222. The xenon lamp 1152 is lit during the image reading period.

  FIG. 13 is a timing chart illustrating an example of signals exchanged between the input image processing unit 1222 and the CIS 1150 when performing variable magnification reading at a variable magnification of 1/2.

  In the example shown in FIG. 13, a line synchronization signal is generated by the CIS 1150 every 70.5 μsec that is the back surface reading line cycle and is input to the input image processing unit 1222. Also, generation of an electronic shutter control signal indicating release of the electronic shutter is started in CIS 1150 in synchronization with the line synchronization signal, and is input to the input image processing unit 1222 for 70 μsec set by the electronic shutter setting. An image signal is input from the CIS 1150 to the input image processing unit 1222 within the back surface scanning line period. The lamp lighting signal is input during the image reading period.

  That is, in the example shown in FIG. 13, the CIS 1150 starts reading image data for one line on the back side of the document every 70.5 μsec, and releases the electronic shutter for a period of 70 μsec and accumulates light. Then, the CIS 1150 reads the image data for one line on the back side of the document and outputs it to the input image processing unit 1222 within a period of 70.5 μsec. The xenon lamp 1152 is lit during the image reading period.

  In the case of the example shown in FIG. 13, the image data for one line on the surface of the document read by the image reading unit 1110 is mechanically scaled to 50% (300 dpi) in the sub-scanning direction. However, the image data on the back side of the document read by the CIS 1150 is not scaled. For this reason, when the image data on the back side of the document is transferred from the CIS 1150, the input image processing unit 1222 electrically scales to 50% (300 dpi) in the sub-scanning direction.

  Hereinafter, the processing from step S1122 to S1124 is the same as the processing from step S122 to S124 in the flowchart shown in FIG.

  As described above, also in the second embodiment, even when the resolution is fixed, the reading line speed is increased according to the reduction rate, and the reading line cycle is shortened according to the reduction rate. Therefore, the reduction in the reading speed of the document and the reduction in productivity can be prevented, and the same productivity as in the case of performing the mechanical scaling can be maintained.

  In the second embodiment, since the electronic shutter setting of the CIS 1150 is controlled to be equal to or lower than the lower limit value of the reading line cycle, the light accumulation time can be kept constant even if the reading line cycle is changed according to the magnification. Further, it is possible to prevent a change in reading characteristics and a deterioration in image quality. Note that the xenon lamp 1152 is designed to have an illumination system having an illuminance necessary to satisfy the reading performance (S / N) of the scanner device 1100.

(Modification 5)
In the second embodiment described above, the same modifications as the modifications described in the first embodiment can be performed.

10, 1010 MFP 100, 1100 Scanner device 110 Image reading unit 112 Slit glass 114 Contact glass 116 Reference white plate 118 Lamp 120 First mirror 122 First carriage 124 Second mirror 126 Third mirror 128 Second carriage 130 CCD image sensor 132 Lens unit 134 Signal processing board 140 ADF
142 Document tray 144 Reference white roller 146 Paper discharge tray 148 Document transport mechanism 150, 1150 CIS
152 LED
210, 1210 Image processing unit 212 Data conversion unit 214 Data conversion unit 216 CPU
218 CPU memory 220 Memory control unit 222, 1222 Input image processing unit 224 Bus 226 Memory 228 Output image processing unit 230 LD driver 240 Controller 242 CPU
244 Image controller 246 I / O controller 248 Input unit 1152 Xenon lamp

JP 2009-33723 A JP 2005-217561 A

Claims (13)

First image reading means for reading the first image data by scanning one side of the document with a first resolution corresponding to the magnification and a first reading period set in advance;
A second image reading unit that turns on a light source, irradiates the other surface of the document, receives and accumulates reflected light from the document, and converts the image into second image data ;
The second image reading means scans the other surface of the document at a second reading period corresponding to the fixed second resolution and the variable magnification, and is a time for accumulating reflected light from the document. An image reading apparatus characterized by controlling an accumulation time to be constant.   The image reading apparatus according to claim 1, wherein the second image reading unit controls the light accumulation time to be equal to or lower than a lower limit value of the second reading period.   The image reading apparatus according to claim 2, wherein the second image reading unit controls lighting of the light source to control the light accumulation time to be equal to or less than the lower limit value.   The second image reading means scans the other side of the document for one line in accordance with a line synchronization signal input every second reading cycle, and input is started in synchronization with the line synchronization signal. The image reading apparatus according to claim 3, wherein the light source is turned on in accordance with a turn-on signal that is input below the lower limit value.   The second image reading means scans the other side of the document for one line in accordance with a line synchronization signal input every second reading cycle, and input is started in synchronization with the line synchronization signal. The image reading apparatus according to claim 2, wherein the light emitted from the light source is accumulated according to a control signal that is input below the lower limit value.   The image reading apparatus according to claim 1, further comprising a conveyance unit that conveys the document at a conveyance speed according to the variable magnification.   The image reading apparatus according to claim 1, further comprising a scaling unit that electrically scales the second image data at the scaling factor. In the first mode, the first image reading unit scans one surface of the document with the first resolution and the first reading period corresponding to the magnification, and reads the first image data. in mode, it reads the first image data by scanning one surface of the document in the first resolution and said first reading a predetermined cycle,
In the first mode, the second image reading unit scans the other surface of the document at the second reading cycle according to the second resolution and the magnification, and reads the second image data. in the second mode, the scanning the other surface of the document in the second resolution and a second reading period predetermined reading the second image data,
8. The image reading apparatus according to claim 7, wherein the scaling unit further electrically scales the first image data read in the second mode with the scaling factor.   The image reading apparatus according to claim 8, wherein the first mode is a productivity mode that prioritizes productivity, and the second mode is a reusability mode that prioritizes reusability.   The image reading apparatus according to claim 8, wherein the first mode is a first application mode, and the second mode is a second application mode. In the single-sided reading mode, the first image reading unit scans one side of the document with the first resolution and the first reading period corresponding to the magnification, and reads the first image data, thereby performing double-sided reading. in mode, it reads the first image data by scanning one surface of the document in the first resolution and said first reading a predetermined cycle,
The second image reading unit, in the duplex scanning mode, wherein by scanning the other surface of the document in the second resolution and a second reading period predetermined reading the second image data,
8. The image reading apparatus according to claim 7, wherein the scaling unit further electrically scales the first image data read in the double-sided reading mode with the scaling factor.   An image forming apparatus comprising the image reading apparatus according to claim 1.   The image forming apparatus according to claim 12, further comprising mode input means for inputting a mode.

Images